external/conscrypt: tweaks for next BoringSSL import.

Upstream BoringSSL has dropped |SSL_ST_BEFORE| (which appears to have been
unused) and all the |*_LOCK_*| symbols. The latter are replaced with
|*_up_ref|, with #if's so that it continues to work with OpenSSL.

Change-Id: Ib609c83d428b7624e24e3b96c93afc2e482e6a6d
2 files changed